Patent GB-697670-A (GB)
Title: Improvements in and relating to the manufacture of lubricating greases
IPC: C10M169/00
Filed: 1950-12-18
Abstract: A lubricating oil is gelled with an inorganic colloid and the mixture heated at a temperature between 120 DEG C and 220 DEG C for a period of between 20 minutes and 180 minutes.  Mineral lubricating oil is preferred, but other specified oils are the alkylated aromatic hydrocarbons such as tertiary butyl napthalenes, polymerized olefins such as liquid polyethylenes, polybutylenes and polycetenes, vegetable and animal oils, non-hydrocarbon synthetic lubricants such as bis(2-ethylhexyl) sebacate, bis(methylethyl) succinate and other diesters of di-carboxylic acids, inorganic esters such as tributyl phosphate, trioctyl phosphate, tricresyl phosphate and dioctyl cresyl phosphate, polymeric silicones, liquid fluorocarbons and halogenated hydrocarbons such as hexachlorobutadiene.  Mixtures of these p lubricants may be used.  Specified inorganic colloids include colloidal alkaline earth metal oxides, hydroxides and carbonates, polyvalent metal oxides such as magnesia, alumina, ferric oxide, vanadium pentoxide, silica, polyvalent metal sulphides such as ferrous sulphide and cuprous sulphide, some metallic sulphates and phosphates and treated clays.  Mixtures of these materials such as synthetic zeolites may be used.  Naturally occuring colloidal inorganic materials may also be employed such as the magnesium silicates, aluminium silicates, magnesium-aluminium silicates; bentonites, Fuller's earth, Hectorite and Wyoming montmorillonite are specified.  The colloidal material may be in a highly expanded form such as an aerogel.  If desired, a hydrogel may be formed and converted without drying to an alcogel which in its turn is converted to an organogel with lubricating oil or benzene.  It is preferred to treat the inorganic colloidal material with from 1 to 30 per cent by weight of an acid such as phosphoric acid or boric acid prior to its incorporation in the lubricating oil.  Clays and synthetic zeolites may preferably be treated with an amine or quaternary ammonium compound such as dimethyl dioctadecyl ammonium chloride to replace sodium ions present and render the clay hydrophobic. The heating of the lubricating oil and the inorganic colloid is preferably carried out between 150 DEG  and 200 DEG C and more especially between 165 DEG  and 200 DEG C, and the preferred time of heating is from 30 to 120 minutes, at atmospheric pressure or under vacuum or super-atmospheric pressure.  The mixture may be stirred, milled or otherwise subjected to shearing during the heating.  The addition of a surface-active agent (preferably cation-active), to the composition during the heating is preferred.  Such surface-active agents include aliphatic amines or polyamines having at least eight carbon atoms and salts and amides thereof, and quaternary ammonium compounds having at least one aliphatic chain of eight or more carbon atoms.  Typical compounds are heptadecylamine, dimethyl benzyl octadecyl ammonium chloride, amines obtained by the ammonolysis of chlorinated paraffin wax, salts of fatty acids having at least seven carbon atoms with polymeric adducts such as those from acrolein and ammonia, or from diallylamine and hydrogen sulphide, partial amides of fatty acids having at least seven carbon atoms with polyalkylene polyamines such as the oleic acid amide of tetraethylene-pentamine, and condensation products of a polyamine with an alkyl or alkenyl succinic or succinamic acid or their anhydrides or acid esters, such as ethylene diamine condensed with dodecenyl succinic acid or octadecyl succinamic acid.  Water-insoluble soaps such as aluminium stearate, aluminium 12-hydroxy stearate, lead stearate and other hydrophobic polyvalent metal salts of organic acids may be used.  It is preferred that the greases contain 2 to 10 per cent by weight of the inorganic colloidal material based on the total composition and 10 to 50 per cent by weight of one or more of the surface-active agents calculated on the weight of the inorganic colloid.  In an example Wyoming bentonite is dispersed in water and gelled by the addition of a high molecular weight aliphatic quaternary ammonium salt.  The resulting hydrogel is washed and added to mineral lubricating oil and formed into a grease by heating at 150 DEG C for 20 minutes followed by milling. Specifications 672,650, 672,651, 683,969, and 685,146 and U.S.A. Specification 2,260,625 are referred to.  Specification 706,772 also is referred to.